Power semiconductor package and method for fabricating a power semiconductor package

Abstract

A method for fabricating a power semiconductor package includes: providing a leadframe having a die pad and a frame, wherein the die pad is connected to the frame by at least one tie bar; attaching a semiconductor die to the die pad; laser cutting through the at least one tie bar, thereby forming a cut surface; and after the laser cutting, molding over the die pad and the semiconductor die, wherein the cut surface is completely covered by molding compound.

What is claimed is: 
     
         1 . A method for fabricating a power semiconductor package, the method comprising:
 providing a leadframe comprising a die pad and a frame, wherein the die pad is connected to the frame by at least one tie bar;   attaching a semiconductor die to the die pad;   laser cutting through the at least one tie bar, thereby forming a cut surface; and   after the laser cutting, molding over the die pad and the semiconductor die, wherein the cut surface is completely covered by molding compound.   
     
     
         2 . The method of  claim 1 , further comprising:
 laser cutting a mold locking feature into the die pad, wherein the mold locking feature comprises a through-hole or a cavity; and   filling the mold locking feature with the molding compound.   
     
     
         3 . The method of  claim 1 , wherein the laser cutting comprises laser cutting through the at least one tie bar in two different locations such that a length of tie bar is cut away completely. 
     
     
         4 . The method of  claim 3 , further comprising:
 using an air stream, a gas stream, or a negative pressure to remove the length of tie bar from the leadframe.   
     
     
         5 . The method of  claim 1 , further comprising:
 after the laser cutting, removing a burr from the cut surface with the laser.   
     
     
         6 . The method of  claim 1 , wherein the at least one tie bar comprises at least one notch, and wherein the laser cutting is performed in the at least one notch. 
     
     
         7 . The method of  claim 1 , wherein the leadframe further comprises leads contiguous with the die pad, and wherein during the molding the die pad is connected to the frame by the leads. 
     
     
         8 . The method of  claim 7 , further comprising:
 after the molding, singulating the power semiconductor package from the frame by cutting through the leads.   
     
     
         9 . The method of  claim 1 , wherein the molding is performed using a molding tool with retractable pins, wherein the retractable pins are configured to fix the die pad in place, and wherein the retractable pins are retracted during the molding. 
     
     
         10 . The method of  claim 1 , further comprising:
 before the laser cutting, coupling an electrical connector to the semiconductor die, wherein the electrical connector comprises a bond wire, a ribbon, or a contact clip.   
     
     
         11 . A power semiconductor package, comprising:
 a die pad comprising at least one tie bar stump, wherein a cut surface is arranged at the end of the at least one tie bar stump;   a semiconductor die attached to the die pad; and   an encapsulation encapsulating the semiconductor die, wherein the encapsulation completely covers the cut surface, and   wherein the cut surface comprises a laser-cut microstructure.   
     
     
         12 . The power semiconductor package of  claim 11 , wherein the at least one tie bar stump faces a first lateral side of the encapsulation, and wherein no metal part is exposed from the encapsulation at the first lateral side. 
     
     
         13 . The power semiconductor package of  claim 11 , further comprising:
 at least one through-hole extending through the die pad, wherein the at least one through-hole is filled with a material of the encapsulation, and wherein the at least one through-hole comprises a further cut surface comprising a laser-cut microstructure.   
     
     
         14 . The semiconductor package of  claim 11 , wherein the at least one tie bar stump comprises a notch, and wherein the cut surface is arranged in the notch. 
     
     
         15 . The semiconductor package of  claim 11 , wherein the cut surface is free of any burr.